Consumption question

[Mu8st7ang1]

So I haven't dosed In a few days and been taking readings on my 90 gal. I want to see what the daily consumption is per day so I can buy and use an auto doser. My tank seems to use .6dkh of alk 10ppm calcium and 10ppm of magnesium per day. Do these numbers seem online with what others are having consumed as well?


Sent from my iPhone using Tapatalk

 

[oh207]

The calcium and Mg consumption seems kind of high, relative to Alk consumption.
What type of corals do you have in tank?
Also, what test kits are you using?

Sent from my SM-N920P using Tapatalk

 

[Mu8st7ang1]

Sps dominate I do have a large clam as well. I'm using salifert I feel that's the most accurate I have Hanna just don't feel it's as accurate


Sent from my iPhone using Tapatalk

 

[piranhapat]

I have the same size tank with a 40 gal sump. Also plumed into DT is 15 gal frag tank. Your numbers are pretty much like my if a shout off my doser for a day. Cal maybe a little less. I have 30 pieces of SPS. Some frags and medium to large size SPS.

 

[Mu8st7ang1]

I have the same size tank with a 40 gal sump. Also plumed into DT is 15 gal frag tank. Your numbers are pretty much like my if a shout off my doser for a day. Cal maybe a little less. I have 30 pieces of SPS. Some frags and medium to large size SPS.

How much do you dose? My cal
Is 430 alk 9.8 I like it high but my mag is 1250 need that up

 

[Boomer]

Mu

Yes, as pointed out, your Calcium consumption is to high . Matter of fact it is 2x to high. That 0.6 dKH should only be about 5 ppm not 10 ppm. Your error is one of the 3. You, the Alk kit or the Hanna meter. I agree with your assumption it is that Hanna. They have always had issues for many. Often it is the sample is not shaken long enough before you take the reading. Your Calcium and Alk are fine. As you mentioned your Mg++ iis a bit low. Shoot for around 1325.

A good guide for Calcium vs Alk consumption

For every 20 ppm Calcium you lose, you lose 2.8 dKH. You can not say this backwards.

 

[Mu8st7ang1]

Boomer
Just so I understand correctly
The .6 of alk a day in consumption and the 10ppm of calcium are too much? I stopped with the Hanna strictly use the salifert for awhile now


Sent from my iPhone using Tapatalk

 

[Boomer]

Mu

You have a testing error. A 10 ppm Calcium drop should give a drop in the Alk of 1.4 dKH, not. 0.6 drop. And a 5 ppm drop in Calcium would give about a 0.6 drop in dKH. That 5 ppm Calcium missing just really can't happen. If not a Calcium testing error then a Alk testing error. Where your drop in Alk should be 1.4 for that 10 ppm not 0.6 dKH. You can't 't lose 10 ppm and only 0.6 dKH.


Yes, a heavy dominated SPS tank can lose 10 ppm but that dKH drop would be much higher, like I said 1.4 dKH and not 0.6 dKH.

 

[Mu8st7ang1]

Great thank you for the explanation I wasn't understand I do now I will check everything again


Sent from my iPhone using Tapatalk

 

[oh207]

+1 to what boomer said. He is the resident expert on this topic.
I had also wanted to say that your Calcium consumption is 2x higher than normal but couldn't figure a valid reason why that would be. Testing error or issues with the test kit is a good place to look.

How much do you dose for Cal and Alk? And which 2-part solution are you using?

I'll try to explain this based on the dosing amounts required.
For example, if you are using BRS 2-Part:
A 10ppm drop in Cal would require 92ml dose for a 90g tank.
And a .6dKH consumption would require 38.5ml dose for a 90g tank.
As you can see the Cal dosage amount is more than twice the Alk. This doesn't make sense.

In our tanks Alk is used up a lot faster than Calcium. Due to the fact that Calcium is present in greater quantity than Alk.

 

[Mu8st7ang1]

Would the fact that I'm just now forming coralline algae on the glass have any impact. This tank is 7 years old


Sent from my iPhone using Tapatalk

 

[oh207]

Would the fact that I'm just now forming coralline algae on the glass have any impact. This tank is 7 years old


Sent from my iPhone using Tapatalk

In a balanced system, there would be no logical explanation, at least none that I can think of. Because as pointed our earlier, if there was indeed a 10ppm consumption of Calcium then you should see a greater consumption of Alk (>.6dKH).

 

[Boomer]

Mu, as per OH

Yes, Coralline will lower the Calcium and Alk but also the Magnesium. And if you were also losing Magnesium that would make it even more so. Meaning, the Alk drops 0.60, the Calcium 10 ppm and say the Magnesium 10 ppm you should lose more like 2.8 dKH vs 0.60. These things just can't happen = testing error.

Take 1/2 liter of seawater and measure the Calcium and Alk then add 1/2 liter of RO/DI water. Then test again. Your calcium and Alk should drop to about half of what it was.

 

[Mu8st7ang1]

So this might be a dumb question I seem to have a lot of them. I have been dosing magnesium to get it up from 1200 to 1380. Once I got it up there I did a water change to get my salinity up I didn't realize it dipped to 33.5ppm so I used 36.5 ppm to get it up to 34.5. Ok back on topic after the water change my mag is 1380 alk 8.8 and calcium 455. I did the water change 2 nights ago. Haven't dosed since yesterday I checked the water and got the results above today I tested same time and again same exact results. So my dumb question is will higher salinity and mag cause less consumption of alk and cal?


Sent from my iPhone using Tapatalk

 

[Mu8st7ang1]

Ok so after my water change I also went out and bought new salifert test kits here is what my daily consumption looks like. Alk.3 per day and calcium .15 per day so I'm losing double the alk per day does this sound a tire more accurate?


Sent from my iPhone using Tapatalk

 

[Boomer]

Yes, better. Alk goes mostly to 3 chemical process, 1) Biotic precipitation to Corals and coralline algae to build thier calcium carbonate structure.2) Abiotic precipitation, on pumps, sand and glass, as calcium carbonate and 3) To help buffer the water from acids that are produced, so you have less falling pH problems unless it is a CO? problem then it is a different story. As CO2 is produced or enters the system it is irrelevant what the Alk is, pH will still fall.